Article
Astronomy & Astrophysics
Kohei Kamada, Fumio Uchida, Jun'ichi Yokoyama
Summary: The decay of hypermagnetic helicity at electroweak symmetry breaking may have produced baryon asymmetry, however, fully helical magnetic field may not be strong enough to explain the origin of intergalactic magnetic field; the combination of helical and nonhelical primordial magnetic fields may explain both, but is ruled out by the constraint on amplitude of baryon isocurvature perturbations.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Antonio Ambrosone, Roberta Calabrese, Damiano F. G. Fiorillo, Gennaro Miele, Stefano Morisi
Summary: A new baryogenesis mechanism was proposed by Dolgov and Pozdnyakov, where baryon asymmetry is produced without violating baryon number at the Lagrangian level. However, further analysis revealed fundamental issues in the scenario, including the initial increase in baryon asymmetry by PBH absorption followed by complete absorption at later times. Additionally, the proposed CP-violation model in this framework was found to be qualitatively correct but quantitatively inconsistent with observed baryon asymmetry.
Article
Astronomy & Astrophysics
Sugumi Kanno, Ann Mukuno, Jiro Soda, Kazushige Ueda
Summary: Dark gauge fields have been proposed as potential candidates for dark matter, and if they exist, primordial dark magnetic fields would have existed during inflation. It is believed that primordial gravitational waves arise from quantum fluctuations during inflation. This study investigates the conversion of gravitons into dark photons in the presence of background primordial dark magnetic fields and finds that this process induces a tachyonic instability in the primordial gravitational waves, leading to a peak in their power spectrum. The height of the peak depends on the observation direction, and the peak frequency can range from 10-5 to 103 Hertz for GUT scale inflation, suggesting that the observation of primordial gravitational waves could be a new way to probe primordial dark magnetic fields.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Sugumi Kanno, Ann Nakato, Jiro Soda, Kazushige Ueda
Summary: There is observational evidence for the existence of primordial magnetic fields generated during inflation. We investigate primordial gravitational waves during inflation in the presence of magnetic fields sustained by a gauge kinetic coupling. In this model, both gravitons as excitations of primordial gravitational waves, and photons as excitations of electromagnetic fields are strongly squeezed, and become entangled through graviton to photon conversion. We calculate the entanglement entropy of the gravitons and find that their state is a mixed state rather than a squeezed state.
Article
Astronomy & Astrophysics
Rajeev Kumar Jain, P. Jishnu Sai, Martin S. Sloth
Summary: This study calculates the primordial correlation between gravitons and a non-minimally coupled abelian gauge field in the early universe, and finds that this correlation satisfies new consistency relations in the three-point cross-correlation functions. The study shows that the interaction between gravitons and gauge fields may have implications for cosmological observables today.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Nicolas Bernal, Chee Sheng Fong, Yuber F. Perez-Gonzalez, Jessica Turner
Summary: The interplay between light primordial black holes (PBH) and high-scale baryogenesis can lead to the creation of leptons in a specific parameter space.
Article
Astronomy & Astrophysics
Masahiro Kawasaki, Shusuke Ueda
Summary: This paper investigates the supersymmetric implementation of Affleck-Dine inflation, which successfully achieves inflation and baryogenesis, and shows that the isocurvature perturbation can be ignored, thus being consistent with observations.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Estanis Utrilla Gines, Olga Mena, Samuel J. Witte
Summary: While primordial black holes cannot comprise the entirety of dark matter, their existence has important consequences for astrophysics. A population of these black holes can efficiently accrete dark matter, leading to high-density dark matter spikes. This study reconsiders the constraints on WIMP annihilation in these spikes, with a focus on a scenario where dark matter is primarily composed of weakly interacting massive particles and has a small subdominant contribution from primordial black holes. The findings suggest that the constraints derived from the isotropic gamma-ray background have been overestimated, while those derived from the cosmic microwave background are typically stronger or comparable.
Article
Astronomy & Astrophysics
Georgios Aliferis, Vasilios Zarikas
Summary: A successful baryogenesis mechanism is proposed in the cosmological framework of Brans-Dicke modified gravity, involving features such as primordial black hole production, Hawking radiation reheating, domain wall formation, and no need for a first-order phase transition.
Our proposed scenario provides black hole domination and efficient baryogenesis for smaller CP-violating angles compared to the same mechanism applied in a Friedmann-Robertson-Walker cosmological background.
Article
Astronomy & Astrophysics
Massimo Giovannini
Summary: This article investigates the large-scale magnetic fields generated by the quantum mechanical fluctuations of hypercharge, combined with the evolution of gauge coupling during a long inflationary stage. The results show that the magnetic power spectra can be amplified when the post-inflationary expansion rate is slower than radiation. Furthermore, the study emphasizes that the modulations of the gauge power spectra freeze when the relevant wavelengths reenter the Hubble radius, and the late-time values of the magnetic power spectra can be accurately computed based on these observations.
Article
Astronomy & Astrophysics
Yann Cado, Mariano Quiros
Summary: We study a modification of the Higgs inflation scenario by introducing an extra scalar field phi, which is coupled to the Ricci scalar and mixed with the Higgs field h. By coupling phi to the Chern-Simons term, helical magnetic fields are generated during inflation. This model can solve the instability problem of the Standard Model and predicts modifications that can be explored at future colliders.
Article
Astronomy & Astrophysics
Yi-Peng Wu, Kalliopi Petraki
Summary: By using a multi-field stochastic approach, this study examines the vacuum expectation value during inflation and suggests a mechanism for baryogenesis, concluding that the charged scalar mass at the order of H-* is favored by the isocurvature constraints at a Hubble scale of 10^13 GeV.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Debabrata Chandra, Supratik Pal
Summary: In this article, we investigate the competency of upcoming Cosmic Microwave Background (CMB) and Galaxy surveys in probing the features in the primordial power spectrum. We focus on three major features, including the Bump feature, Sharp feature signal, and Resonance feature signal, and analyze their constraints using different observational data. The research findings suggest that these upcoming observations have relative capabilities in shedding light on crucial aspects of precision cosmology.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Particles & Fields
S. Abbaslu, S. Rostam Zadeh, M. Mehraeen, S. S. Gousheh
Summary: The study reveals that, in the symmetric phase of the early Universe, the temperature-dependent chiral vortical effect can lead to the generation of strong hypermagnetic fields and matter-antimatter asymmetries from zero initial values, through small transient fluctuations in the vorticity field and temperature of matter degrees of freedom. Additionally, an increase in the amplitudes of the fluctuations of vorticity or temperature, or a decrease in their widths, results in the production of stronger hypermagnetic fields and larger matter-antimatter asymmetries. The intriguing finding is that fluctuating vorticity fields are significantly more productive compared to those that are constant in time.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
S. Abbaslu, S. Rostam Zadeh, A. Rezaei, S. S. Gousheh
Summary: The study focuses on the evolution of matter-antimatter asymmetry, vorticity, and hypermagnetic field in the symmetric phase of the early Universe, demonstrating that increasing the initial vorticity accelerates the saturation of helicity, matter-antimatter asymmetry, and vorticity values, without changing their final values at the onset of the electroweak phase transition.
Article
Physics, Particles & Fields
Yohei Ema, Kyohei Mukaida, Jorinde van de Vis
Summary: The paper derives one- and two-loop renormalization group equations (RGEs) of Higgs-R-2 inflation, valid as long as the energy scale of interest is below the Planck scale. The model's non-minimal coupling and squared term have significant implications for inflationary predictions and the electroweak vacuum stability.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Multidisciplinary
Keisuke Inomata, Masahiro Kawasaki, Kyohei Mukaida, Tsutomu T. Yanagida
Summary: The study suggests that the axionlike curvaton model can explain the primordial black holes in both the LIGO-Virgo events and NANOGrav results, with the non-Gaussianity suppressing the gravitational waves associated with PBHs.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Particles & Fields
Tobias Binder, Kyohei Mukaida, Bruno Scheihing-Hitschfeld, Xiaojun Yao
Summary: This article presents a complete next-to-leading order calculation of the non-Abelian electric field correlator in a SU(N-c) plasma, providing insights into the properties of the plasma that are relevant for heavy particle bound state formation and dissociation.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Yohei Ema, Kyohei Mukaida, Kazunori Nakayama
Summary: The hidden sector scalar field generically couples to quadratic curvature through dimension five operators, potentially inducing decays into graviton pairs. Decay of the scalar field can produce a significant amount of stochastic cosmic graviton background at high frequencies due to the suppression scale being determined by the mass of heavy particles rather than the Planck scale. The resulting graviton spectrum is computed in specific models, highlighting the phenomenological interest of these scalar couplings.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Multidisciplinary
Valerie Domcke, Camilo Garcia-Cely, Nicholas L. Rodd
Summary: The study indicates that rapid progress is expected in detecting gravitational waves, especially through increasing the volume of instruments and making simple modifications to the pickup loop. While the current strain sensitivity to gravitational waves is weak, breakthroughs are expected in the future.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Kyohei Mukaida, Kai Schmitz, Masaki Yamada
Summary: Charged-lepton flavor violation (CLFV) is a distinct feature of physics beyond the standard model, which plays an important role in the early universe. This Letter points out that efficient CLFV interactions create new pathways for generating the baryon asymmetry of the universe, and the conversion factor from lepton flavor asymmetry to baryon asymmetry is naturally explained by the suppression of charged-lepton Yukawa couplings squared.
PHYSICAL REVIEW LETTERS
(2022)
Article
Astronomy & Astrophysics
Tomohiro Fujita, Jun'ya Kume, Kyohei Mukaida, Yuichiro Tada
Summary: This study focuses on the axionic inflaton model with the Chern-Simons coupling and finds that the backreaction from charged particles suppresses the amplitude of gauge fields, leading to the dominance of charged particles in the evolution. The findings provide a basis for connecting inflationary models to phenomena such as baryogenesis and magnetogenesis.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Particles & Fields
Yu Hamada, Ryuichiro Kitano, Ryutaro Matsudo, Kyohei Mukaida
Summary: The Maxwell equations suggest that a varying theta term can produce E·B under the background of a non-zero magnetic field B. The underlying mechanism of the Witten effect, where a magnetic monopole becomes a dyon, has been understood by the presence of an effective axion-like degree of freedom. The chiral anomaly implies that a non-zero E·B induces chiral charge in the system, and the discussion explores whether this chiral charge is generated in the massless limit when considering the axion-like degree of freedom.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Kyohei Mukaida, Masaki Yamada
Summary: This paper investigates the thermalization of high-energy standard model particles in thermal plasma, considering the Landau-Pomeranchuk-Migdal effect. The distribution function of each particle species is calculated numerically and analytically. The results demonstrate that, after multiple splittings, the particle distributions converge to certain values at low momentum, independent of the high-energy particles injected by inflaton decay. This is helpful for calculating the dark matter abundance produced during the pre-thermal phase.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Valerie Domcke, Keisuke Harigaya, Kyohei Mukaida
Summary: We study the transfer of charge between complex scalar fields and find that under certain conditions, this transfer can be very efficient. This has important implications for cosmological studies involving complex scalar fields.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Astronomy & Astrophysics
Tomohiro Fujita, Kyohei Mukaida, Yuichiro Tada
Summary: In this study, we develop a stochastic formalism for U(1) gauge fields coupled with a rolling pseudo-scalar field during inflation. We derive the Langevin equations for the physical electromagnetic fields and study their analytic solutions. Through numerical simulation, we demonstrate that the averaged electromagnetic fields over the Hubble scale continuously change their direction and fluctuate around the analytically obtained expectation values. While the isotropy is spontaneously broken in each local Hubble patch, it is globally preserved by averaging all the Hubble patches.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Particles & Fields
Valerie Domcke, Yohei Ema, Kyohei Mukaida
Summary: This paper investigates the problem of particle production in a time-dependent background, focusing on the transient effects of fermions in a homogeneous axion background. The definition of particles and antiparticles at intermediate times in the presence of external fields is more ambiguous compared to the asymptotic states in conventional cases, and these external fields also lead to divergences that require regularization.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Multidisciplinary
Valerie Domcke, Kohei Kamada, Kyohei Mukaida, Kai Schmitz, Masaki Yamada
Summary: This letter investigates the relationship between helical hypermagnetic fields and fermion asymmetry in the early Universe caused by chiral chemical potential. The study demonstrates that even with zero total lepton number, a mechanism can be triggered through lepton flavor asymmetry. This sets a constraint on lepton flavor asymmetry at temperatures above 106 GeV, which is about two orders of magnitude stronger than current limits from cosmic microwave background and primordial nucleosynthesis.
PHYSICAL REVIEW LETTERS
(2023)
Article
Astronomy & Astrophysics
Enrico Morgante, Nicklas Ramberg, Pedro Schwaller
Summary: We estimate the gravitational wave signal emitted in the confinement transition of a pure SU(3) Yang-Mills dark sector by analyzing the phase transition in improved holographic QCD. We calculate the energy budget and duration of the phase transition with minor errors using the derived effective action from holography. These calculations are then used to predict the gravitational wave signal. This is the first computation of gravitational wave signal in a holographic model designed to match lattice data on the thermal properties of pure Yang-Mills.